CAR-15 Trigger Pin Issue

[C420sailor]

I was going to post on AR15.com, but I trust y'all more.

The rifle is a CAR-15 I built from parts. It has an LRB lower receiver with a standard DPMS lower receiver parts kit. The trigger pin slowly walks itself out with each trigger squeeze, eventually jamming up the trigger as it disengages one side of the lower. Has anyone here seen this before? Any suggestions on a fix?

 

[Rocketman]

I've never had it happen. I think it's more common in full auto weapons.....

First check to be sure the hammer spring arms are in the notches of the trigger pin. I'm not sure how it could be otherwise unless you don't have it assembled correctly but it won't hurt to check that first. If that isn't it either the hammer pin or the hole in the receiver is out of spec. Cheapest thing to do in that case is buy a new trigger pin (or two) and see if that is the problem. If the receiver is out of spec buy a set of Knights anti-walk pins (others make them too) and that should fix it.

 

[statesman]

Ditto on what Rocketman said.

Best thing to do is replace the trigger pin. Other possibility is that its the receiver that wasn't manufactured correctly... the pin would be cheaper to replace.

 

[Rocketman]

yea a trigger pin is a dollar fix if that's what it ends up being. Be sure to check that you didn't assemble the lower with the hammer spring upside down first though. It's easy enough to do on your first build. (ask me how I know) It will work that way most of the time although you may get some light primer strikes.

The hammer spring should be mounted on the hammer so that the legs come out of the coil on the bottom of the coil. Then just be sure when you assemble it that the legs are on top of the trigger pin and that at least one of the legs are in the groove on the pin. Sometimes the groove on the trigger pin is too shallow and once in a long while the diameter is a bit off on either the pin or the receiver.

 

[C420sailor]

You guys are good. I was, in fact, bump firing the rifle when the pin first walked out. It was my first lower receiver build, so there's a good chance I dicked something up. I'll check the hammer spring and report back.

 

[C420sailor]

The hammer spring was installed incorrectly. The legs were sitting on the bottom of the receiver, instead of the pin. I did have a few light strikes today, so hopefully this fixes both issues. Thanks guys!

 

[gaijin6423]

For selfish reasons, I'm glad it wasn't the receiver. I have an LRB lower purchased for a song that I'm just getting around to thinking about setting up.

 

[Rocketman]

I bought 2 of those some time ago as well. I built both of them up and had no problems putting them together. They were easier to put together than my last couple of Spikes lowers. I was confident enough that they were good to go that I sold them to friends. They are still running just fine so you should be plenty good....

Speaking of lowers for a song check this out........ http://www.palmettostatearmory.com/1560.php (oops these lowers were $49.95 over the weekend for Memorial day sale.... now they are back up to $79.95 but still a good deal at that price.)

 

[Gatordev]

Speaking of lowers for a song check this out........ http://www.palmettostatearmory.com/1560.php (oops these lowers were $49.95 over the weekend for Memorial day sale.... now they are back up to $79.95 but still a good deal at that price.)

A word of warning on the PSA lowers. I bought one for my .22 carbine (for $69 at the time) and everything went together very easily (second lower I had assembled) with a G&R kit, however, the aft "shelf" where the aft take-down pin receiver comes down is just slightly out of spec. It's apparently just a little too high, so when you bring the upper down, you really have to push the aft take-down pin in to make it go in, or push down on the upper harder than you would normally do. The same upper mated up fine on my Spike's and Mega lowers, so it's not the upper.

All that said, once put together, it's been problem free and I probably have at least 500 rounds through it, including some .22 carbine competitions, all without issue. I just have to tap out the aft pin a little bit when I break it down to clean it.

 

[Rocketman]

Good to know, I haven't done a build with PSA yet. Believe it or not I had the same issue with a Noveske lower/upper a couple of weeks ago. About 6 months ago I built two Noveske lowers. One using a Colt LPK and another using a G&R LPK. The lowers mated up with just fine with the BCM uppers I put on them. I decided not to long ago to bite the bullet and buy 2 BCM lowers (from Grant at G&R by the way) and 2 Noveske uppers (from Ranier) so I'd have everything all matched up. I sleep better when things match... Anyway one of the Noveske upper/lower combinations fit so tightly that I had to tap the aft pin in with a plastic hammer. Had to use a polymer punch to get the damn thing apart. I'd heard that Noveske rifles are a tight fit but this was way too tight. The crazy thing is that when I swapped the Noveske uppers and lowers around everything fit just fine....tight but not tight enough that I have to use tools to get them apart.

I've run thru about 2000 rounds in the last 2 weeks breaking in my new toys (2 middies and 2 carbines, 1 each 14.5" pinned and 1 each 16")

 

[Gatordev]

Another PSA plug... I'm trying to figure out "the catch." While a PSA barrel might not match BCM or Noveske, this seems to still be one helluva deal. I don't really "need" nor want another 5.56 upper right now, but it has me thinking.

http://palmettostatearmory.com/2557.php

Then again, I could just buy a PSA lower and then buy a H-1 w/Larue mount from Larue and still come out "cheaper." Or even a PRO and PSA lower...

 

[Rocketman]

Another PSA plug... I'm trying to figure out "the catch." While a PSA barrel might not match BCM or Noveske, this seems to still be one helluva deal. I don't really "need" nor want another 5.56 upper right now, but it has me thinking.

http://palmettostatearmory.com/2557.php

Then again, I could just buy a PSA lower and then buy a H-1 w/Larue mount from Larue and still come out "cheaper." Or even a PRO and PSA lower...

I don't think there is a catch. I think it's one hell of a deal too. PSA has lots of people talking with this offer which I'm sure was the goal behind pricing like that. I don't personally know the owner but he was nice enough to give me a tour of his new place and discuss some of his plans when they first opened it. I drive from Charlotte to Columbia several times a month to visit a customer. Every time I do I stop in to look around. They have a nice retail shop and a huge warehouse with plenty of room to grow. All indications are they are listening to the market and really trying to do things right. Doesn't hurt when FN is right around the corner either...

Since you mentioned it IMHO if you don't have a T-1 or H-1 you need to get one at some point. I like the EoTech reticle better and it's still just a little faster for me but I've grown to love my little T-1's. It's size and never having to turn it off and still getting crazy battery life is a big deal to me

 

[Gatordev]

I continue to be a big fan of PSA. I keep buying my 5.56 ammo from them and have been very happy.

I broke down and bought a JD Machine lower today at the local gun show for $99. It's not a PSA lower price, but after a transfer fee, CA DROS and tax, I think I've come out ahead. So, after buying that and a few bits for it, I could buy a H-1 from Larue and still come out ahead compared to if I had gone with the PSA full package (and CA DROS and tax and transfer fee...notice a trend?) with the PRO. And like the Cylons, I have plan...and I think it might involve a 5.45 upper...probably from Adams Arms, but that's down the road.

Oh, and I almost pulled the trigger on a Gen 3 G17 today at the gunshow, but I think I can still get it cheaper if I do a Blue Label buy. I just need to do more research. My basic problem is that guns are far more interesting than my work right now.

 

[gaijin6423]

What kind of Gen 3? It's a personal opinion, but I hate the fucking fish gill cocking serrations on some of them. I think they mainly came on the RTF 2 guns, but I could be wrong. I shot a match today with my admittedly modified Gen2 G22, and it was so much better than the G17 I used a couple weeks ago.

To keep it at least a bit on track here, though... Match today had one lone rifle stage. And despite the rest of the folks in my squadding assignment sporting $3k+ custom 3-gun rifles, they couldn't hit shit. My little BCM M-4, however could not miss. Of course, I got schooled big time on the pistol stages by the guys, who I found out afterwards are all sponsored, Area Champion, GM-level shooters. Given that my times/hits weren't all that far off from theirs, though, maybe I didn't get as much education as I thought at first.

 

[Rocketman]

I continue to be a big fan of PSA. I keep buying my 5.56 ammo from them and have been very happy.

I broke down and bought a JD Machine lower today at the local gun show for $99. It's not a PSA lower price, but after a transfer fee, CA DROS and tax, I think I've come out ahead. So, after buying that and a few bits for it, I could buy a H-1 from Larue and still come out ahead compared to if I had gone with the PSA full package

Sounds like you done good. As long as it's in spec a lower is a lower. Just something to hang parts off of. I like Noveske lowers because they have a cool roll mark. I like BCM and Noveske uppers because you can't buy better quality. PSA appears to be following their model....especially BCM's model.